Abstract 17329: Prognostic Value of Coronary Flow Reserve in Patients with Prior Coronary Artery Bypass Surgery
Introduction: Although abnormal coronary flow reserve (CFR) is frequently seen after coronary artery bypass graft (CABG) surgery, little is known about its association with clinical outcomes.
Hypothesis: We tested the hypothesis that CFR quantification will provide improved risk stratification in patients with prior CABG.
Methods: We studied 567 consecutive patients (73.5% male; age 73 ± 11 years) undergoing PET myocardial perfusion imaging (MPI) for evaluation of chest pain and/or dyspnea after CABG from 2006 to 2013. The median time between first CABG and PET MPI was 9.9 years, and 45 patients underwent redo CABG before PET study. Ischemia + Scar score was calculated by dividing summed stress score by 68 and multiplying by 100 to obtain a percentage. Rest and stress myocardial blood flow (MBF, in mL/min/g) were quantified, and CFR was calculated as stress/rest MBF. Primary and secondary endpoints were defined as all cause death, and all cause death plus non-fatal myocardial infarction (MI), respectively. Cox proportional hazards model were used to evaluate the association of CFR and outcomes.
Results: The mean CFR was 1.56 ± 0.56. During a median follow up of 2.4 years, 146 deaths and 43 non-fatal MI occurred. The annualized death rate increased with increasing levels of LV ischemia+scar score on PET MPI, and it was highest with each worsening groups of CFR (Figure). In survival analysis adjusting for clinical risk score (Morise), a history of MI, time from CABG, LV ischemia+scar score, and rest LVEF, higher CFR was associated with lower primary (hazard ratio [HR]: 0.93 [95% CI: 0.90 - 0.97] per 0.1 unit increase, p < 0.001) and secondary endpoints (HR: 0.94, [95% CI: 0.91 - 0.97] per 0.1 unit increase, p < 0.001).
Conclusions: Coronary flow reserve measurements, as measured by PET MPI, provide improved risk stratification in patients with prior CABG.
- Cardiac imaging
- Positron emission tomography
- Myocardial perfusion
- Coronary artery bypass grafting (CABG)
Author Disclosures: T. Kato: None. V. Veeranna: None. N.R. Shah: None. V.R. Taqueti: None. V.L. Murthy: None. C.R. Foster: None. M. Gaber: None. J. Hainer: None. J. Klein: None. S. Dorbala: Research Grant; Significant; Astellas Pharma. Ownership Interest; Significant; General Electric. R. Blankstein: None. M.F. DiCarli: None.
- © 2014 by American Heart Association, Inc.